Terminal connection for terminal bushing



March 1965 D. J. MARTAHUS ETAL 3,173,988

TERMINAL CONNECTION FOR TERMINAL BUSHING Filed Feb. 9 1962 FL J Wu n 7 i L: 5 2 l3 Fig.3.

34 26 Flg. I.

Fig.4.

INVENTORS Donald J. Mcrtuhus 8 Robert L. Hess.

ATTORNEY United States Patent 3,173,988 TERMINAL CONNECTION FOR TERMINAL BUSHING Donald J. Martahus, Franklin Township, Westmoreland County, and Robert L. Hess, North Versailles Township, Allegheny County, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 9, 1962, Ser. No. 172,186 3 Claims. (Cl. 17475) This invention relates to terminal connections for terminal bushings in general, and, more particularly, to improved and compact terminal connections for terminal bushings providing interchangeability for circuit-breaker use or transformer use.

A general object of this invention is to provide an improved terminal connection for a terminal bushing which will result in the terminal bushing being of reduced height, yet being adaptable for interchangeable use, such as for transformer use or for circuit-breaker use.

A more particular object of the present invention is to provide an improved terminal connection for a terminal bushing which will provide a weatherproof seal to prevent the entrance of moisture into the interior of the terminal bushing.

Still a further object of the present invention is the provision of an improved terminal connection for a terminal bushing involving few parts and adaptable for economical manufacture.

Yet a further object of the present invention is the provision of an improved terminal connection for a terminal bushing in which the terminal connection may be rapidly assembled into proper position by unskilled workmen, and also may be adapted for good conducting engagement with associated parts for the transmission of relatively high amperage currents.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawing, in which:

FIGURE 1 is a side elevational view of a terminal bushing embodying the present invention as applied to a circuit breaker;

FIG. 2 is an enlarged vertical sectional view taken through the improved terminal connection of the present invention; as applied to circuit-breaker use.

FIG. 3 is a detail plan view of the locking nut of the invention; and

FIG. 4 illustrates the transformer cable connection to the locking nut when the terminal bushing is applied to transformer use.

Referring to the drawing and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a terminal bushing. As shown, the terminal bushing 1 may be associated with the cover 2 of a tank structure 3, the latter providing a suitable enclosure for a transformer or for a circuit interrupter, FIG. 1 illustrating, however, the terminal bushing 1 as applied to circuit-breaker use.

A flange assembly 4 is provided to permit the fixed mounting of the terminal bushing 1 to a neck portion 5 of the tank structure 3. Bolts 6 and cooperating nuts 7 may be employed for this purpose. Extending longitudinally through the terminal bushing 1 is a tubular conductor stud 9. In the case of circuit-breaker use, as shown in FIGS. 1 and 2, the circuit-interrupting unit 8 may be threadedly secured to the external lower threaded surface 9a of the terminal stud 9, and hence fixedly mounted thereto. In the case of transformer use, the flexible connector 10 from the transformer may be fished through the hollow interior 11 of the tubular conductor stud 9 and 3,173,988 Patented Mar. 16, 1965 secured to a locking nut 13, as shown in greater detail in FIG. 4- of the drawings.

With particular attention being directed to FIG. 2, it will be observed that the locking nut 13 has a frusto-conical portion 14, which is adapted to be inserted into a frusto-conically-shaped cavity 15 of a slotted tubular terminal connector 16. A plurality, in this particular instance four, of slots 16a are provided in the lower externally-threaded shank portion 28 of the terminal connector 16. As shown, the slotted tubular terminal connector 16 has an annular sealing flange portion 17 with a peripheral overlying portion 18. Preferably, a resilient gasket 19 is interposed between the sealing flange portion 17 and the upper extremity 9b of the tubular conducting stud 9.

A locking bolt 20 is provided having a cap portion 21, the latter seating within a recess 22 provided at the upper extremity of the tubular terminal connector 16. It will be apparent that by utilizing an Allen-head wrench, not shown, Within a suitably-shaped cavity 24 of the cap portion 21 the locking bolt 2t) may be rotated and consequently, through the threaded connection, as at 26, draw the locking nut 13 upwardly effecting thereby a slight spreading of the slotted threaded shank portion 28 of the terminal connector 16 into firm pressural engagement with the internal surface 30 of the terminal stud 9.

As well known by those skilled in the art, suitable compression springs, not shown, are provided internally of the cap shell 31 to effect compression of the porcelain shell 32, flange assembly 4 and lower porcelain shell 34. The tubular terminal stud 9, of course, is correspondingly subjected to tensile stress. Such compression springs are protected from the weather and are maintained in proper position by the cap shell 31. As shown, the upper peripheral edge 35 of the cap shell 31 is secured, as by a brazed connection 37, to a mounting collar 38, which in turn, is fixedly connected, as by a soldered connection 39 to the upper external surface 40 of the tubular conductor stud 9.

To prevent the entrance of moisture into the cavity 22 provided within the terminal connector 16, preferably a pipe plug 41 having tapered threads is threadedly secured into position, as shown in FIG. 2.

For circuit-breaker use or for transformer use the line connection 35 with its associated apertured terminal 46 may be secured by cooperating nuts 4-3, 44 to the upper external threaded terminal portion, or terminal-attaching portion 45 of the terminal connector 16. For transformer use, the flexible lead 10, connected to the transformer Winding is fished upwardly through the interior 11 of the tubular conductor stud 9 and threadedly secured into the tapped opening 47 provided at the lower end of the locking nut 13, as shown in FIG. 4.

It will be observed that there are required relatively few pieces for the improved terminal connection of the present invention. in addition, the particular arrangement is suitable for terminal connectors for terminal bushings adaptable over a wide range of voltages such as through 196 kv., for example. The same terminal connector may be used for a wide variety of terminal bushings of diiferent voltage ratings.

The construction of the present invention eliminates two large castings, which were previously used in priorart constructions, and also excessive machining and a number of soldered joints. Moreover, the present invention permits the terminal bushing 1 to have a minimum of height, which is advantageous during shipment of the bushing 1 with other attached electrical apparatus.

The improved terminal connector of the present invention merely requires only one casting, or forging, and one machined part made from bar stock, for example; it

reduces labor for installation purposes, eliminates a soldered joint, which was necessitated by prior-art constructions. The construction maintains interchangeability and utilizes a new method for locking threads on the con nector H. Finally, the improved terminal connector of the present invention ensures good conductivity between the several parts.

During recent years the size of transformers and circuit interrupters have considerably increased in size because of the higher MA ratings. The utilization of the improved terminal connector of the present invention permits the length or height of the condenser lead 1 to be reduced, which is an important factor in shipment.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention:

1. in terminal apparatus for use with a terminal bushing of the type having a passageway therethrough, in combination, a tubular conductor stud, the outer end of the tubular conductor stud being internally threaded, a unitary terminal connector having an axial bore therethrough mounted in the outer end of the conductor stud in threaded engagement therein, an external lead secured to the external end portion of said unitary terminal connector, the internal end of said axial bore being tapered, the internal end of said terminal connector adjacent the tapered bore portion being slotted to form resilient finger portions capable of radial outward expansion into pressural engagement with the inner wall of the tubular conductor stud, a locking bolt extending through said axial bore of the terminal connector, a locking nut for the locking bolt having a tapered external side portion, the nut being normally disposed in the tapered wall portion of the bore and tending upon tightening of the locking bolt to expand said finger portions into pressural engagement with the adjacent end of the tubular conductor stud, and an internal lead detachably secured to the locking nut, the internal lead being adapted to be disconnected from the terminal apparatus by unscrewing the locking bolt and releasing the tapered locking nut without disconnecting the external lead from the external end portion of said unitary terminal connector.

2. Terminal apparatus according to claim 1 wherein the axial bore in the unitary terminal connector is additionally characterized as being internally threaded over a portion of the length thereof at the outer end thereof, and including in addition a removable plug in threaded engagement in the internally threaded outer end of said axial here to seal the bore in the unitary terminal connector and seal the inside of the tubular conductor stud from atmospheric moisture, the internal lead being easily removable by removing the plug from the axial bore and thereafter unscrewing the locking bolt.

3. in terminal apparatus for use with a terminal bushing of the type having a passageway therethrough, in combination, a tubular conductor stud, the outer end of the tubular conductor stud being internally threaded, a unitary terminal connector having an axial bore therethrough secured in the external end of the tubular conductor stud in threaded engagement therein, the internal end of said axial bore being tapered, the internal end of said terminal connector adjacent the tapered bore portion being slotted to form resilient finger portions capable of radial outward expansion into pressural engagement with the inner wall of the tubular conductor stud, external lead means secured to the external end of the unitary terminal connector, a locking bolt extending through said axial bore of the terminal connector, a locking nut for the locking bolt having a tapered external side portion, the nut being normally disposed in the tapered wall portion of the bore and tending upon tightening of the locking bolt to expand said finger portions into pressural engagement with the wall of the tubular conductor stud, and internal lead means adapted to be connected to electrical equipment and releasably secured to the locking nut, the internal lead means being releasable without substantially exposing the interior of the conductor stud to atmospheric moisture by unscrewing the locking bolt only far enough to disengage the threads on the tapered locking nut whereupon the tapered locking nut may be withdrawn from the terminal connector together with the attached end of the internal lead means.

Saurman et al Dec. 22, 1931 Burr Aug. 9, 1932 

1. IN TERMINAL APPARATUS FOR USE WITH A TERMINAL BUSHING OF THE TYPE HAVING A PASSAGEWAY THERETHROUGH, IN COMBINATION, A TUBULAR CONDUCTOR STUD, THE OUTER END OF THE TUBULAR CONDUCTOR STUD BEING INTERNALLY THREADED, A UNITARY TERMINAL CONNECTOR HAVING AN AXIAL BORE THERETHROUGH MOUNTED IN THE OUTER END OF THE CONDUCTOR STUD IN THREADED ENGAGEMENT THEREIN, IN AN EXTERNAL LEAD SECURED TO THE EXTERNAL END PORTION OF SAID UNITARY TERMINAL CONNECTOR, THE INTERNAL END OF SAID AXIAL BORE BEING TAPERED, THE INTERNAL END OF SAID TERMINAL CONNECTOR ADJACENT THE TAPERED BORE PORTION BEING SLOTTED TO FORMED RESILIENT FINGER PORTIONS CAPABLE OF RADIAL OUTWARD EXPANSION INTO PRESSURAL ENGAGEMENT WITH THE INNER WALL OF THE TUBULAR CONDUCTOR STUD, A LOCKING BOLT EXTENDING THROUGH SAID AXIAL BORE OF THE TERMINAL CONNECTOR, A LOCKING NUT FOR THE LOCKING BOLT HAVING A TAPERED EXTERNAL SIDE PORTION, THE NUT BEING NORMALLY DISPOSED IN THE TAPERED WALL PORTION OF THE BORE AND TENDING UPON TIGHTENING OF THE LOCKING BOLT TO EXPAND SAID FINGER PORTIONS INTO PRESSURAL ENGAGEMENT WITH THE ADJACENT END OF THE TUBULAR CONDUCTOR STUD, AND AN INTERNAL LEAD DETACHABLY SECURED TO THE LOCKING NUT, THE INTERNAL LEAD BEING ADAPTED TO BE DISCONNECTED FROM THE TERMINAL APPARATUS BY UNSCREWING THR LOCKING BOLT AND RELEASING THE TAPERED LOCKING NUT WITHOUT DISCONNECTING THE EXTERNAL LEAD FROM THE EXTERNAL END PORTION OF UNITARY TERMINAL CONNECTOR. 